The present disclosure generally relates to depth measurement, and specifically relates to using scanning diffractive optical elements for depth measurement in head-mounted display (HMD) applications.
Depth measurement is an important feature for HMD systems, such as systems used in virtual reality (VR) and augmented reality (AR) applications. Depth measurements systems typically include some sort of active illumination system that illuminates a local area (e.g., by projecting structured light, and light pulse, etc.). The depth measurement system then uses images of the local area that include the projected light in order to determine depth information of objects in the local area. Different types of structured light patterns or different fields of view are often required for objects with different shapes or at different locations in the local area. However, existing depth measurement systems have a drawback that a single depth measurement system only projects a single type of structured light pattern or has a single field of view. Accordingly, multiple depth measurement systems often have to be used to determine depth information of different objects, which impair effectiveness of depth measurement and also increases weight, cost, and system complexity of HMD systems.